1. Field of the Invention
The present invention relates to an optical disc device such as a CD player or the like, and more particularly, to a lens cleaner for cleaning the object lens of an optical pick-up for optically reading out signals from a disc.
2. Description of the Related Art
In a CD player, the object lens of the optical pick-up for optically reading out signals from a disc can become soiled by adherence of dust, and the like, from the atmosphere, since the lens is exposed constantly. If soiling of this kind becomes pronounced, then it may cause adverse effects on the quality of the reproduction signal, by producing, for example, sound skipping, noise, degradation of the sound quality, or the like. If the soiling becomes further severe, then reproduction may become impossible and the device may cease to function. Therefore, from the viewpoint of maintaining the level of cleanliness of the surface of the object lens at or above a prescribed level at all times, preserving the quality of the reproduction signal, and preventing a machine from ceasing to operate due to it being in a state where reproduction is impossible, conventionally, lens cleaners of various types have been developed and used in practice.
Amongst lens cleaners of this kind, a disc type lens cleaner having cleaning members, such as brushes, or the like, provided on one side of a disc having the same specifications as a compact disc (hereinafter, abbreviated to CD), has a simple structure and is also easy to use, and therefore this type of cleaner is widely used (see, for example, Japanese Patent Laid-open Application No. H1-43386).
FIG. 7 and FIG. 8 show prior art examples of a lens cleaner of this kind. Of these, the lens cleaner shown in FIG. 7 comprises bristle brushes 2 disposed at two mutually adjacent positions in the radial direction of the disc 1. Furthermore, the lens cleaner shown in FIG. 8 comprises bristle brushes 2 disposed at eight positions in the circumferential direction, the brushes being distributed in a spiral fashion in such a manner that they gradually become further separated from the centre of the disc 1.
Similarly to a normal CD, in the case of these lens cleaners illustrated in FIG. 7 and FIG. 8, the disc 1 is inserted into the CD player and is transported to a reading position, whereupon cleaning of the object lens is performed by using a standard reading operation by the device mechanism, in other words, operation of the optical pick-up in the radial direction of the disc and rotation of the disc 1. More specifically, by means of the operation of the optical pick-up in the radial direction of the disc, positional alignment between the bristle brushes 2 and the object lens is achieved, and by causing the bristle brushes 2 to move with respect to the object lens whilst in a state of contact with same, by rotation of the disc 1, it is possible readily to remove the dirt adhering to the object lens. Furthermore, various types of cleaning agents for lens cleaning have also been developed, and by applying a cleaning agent of this kind to the bristle brushes 2 and then performing the operation described above, it is possible to improve cleaning performance. Moreover, prior art technology has also been proposed for a lens cleaner which cleans a lens by means of a rotating disc, as described previously, wherein lens cleaning is performed by automatically detecting the installation of the lens cleaner, on the basis of the difference in light exposure between a normal disc and a lens cleaner disc (for example, Japanese Patent Laid-open Application No. H1-140482). Furthermore, a cleaning cartridge has also been proposed, wherein a brush and an operating lever are provided in a cartridge case, this cartridge case is installed in an optical disc device, the operating lever, which is exposed to the outside of the device, is operated, and the object lens inside the device is cleaned by means of the brush (see, for example, Japanese Patent Laid-open Application No. S63-313378).
However, problems of the following kind exist in conventional lens cleaners such as those described above.
Firstly, in the case of a method for cleaning an object lens by causing a lens cleaner disc to rotate by means of the device mechanism, there is a drawback in that cleaning of the object lens cannot be carried out unless the disc rotates. More specifically, in general CD players are composed in such a manner that, from the viewpoint of preventing inappropriate operation in the event of a defective disc, if the disc management information cannot be read from a disc satisfactorily by the object lens, such disc is regarded to be a defective disc, and all operation of the device including rotation of the disc is halted. Therefore, if the soiling of the object lens is very bad, then it will not be possible to cause the lens cleaner disc to rotate, and hence cleaning of the object lens will become impossible.
In cases such as these, it is difficult for a general user to clean the object lens by himself or herself, and hence it is necessary that the service department of the manufacturer or the supplier performs the tasks of disassembling the CD player, removing the whole optical pick-up, and replacing it with a new optical pick-up. Therefore, it is difficult for the user to use the CD player over a long period of time, and furthermore, the economic burden on the user is increased.
To deal with this situation, it has been conceived to adopt a device which transfers to a lens cleaning operation by automatically detecting insertion of a lens cleaner as disclosed in Japanese Patent Laid-open Application No. H1-140482. However, since the detection of insertion of a lens cleaner is based on detection of the difference in the light exposure by means of the optical pick-up, then if the soiling of the object lens itself is very bad, there is a possibility that misdetection may occur. Moreover, a special structure is required in the optical disc device in order to detect the lens cleaner, and hence the device becomes more complicated.
Furthermore, even if it is possible to clean the object lens by rotating the disc, since the bristle brushes projecting from the disc also make contact with other regions in addition to the object lens, then the cover of the optical pick-up, and the like, forms an obstacle and the bristle brushes do not make satisfactory contact with the object lens, and hence there is a possibility that effective cleaning will no longer be achievable. Moreover, there is also a possibility that secondary problems may arise, for instance, that grease in the vicinity of the optical pick-up may conversely be applied to the object lens by means of the bristle brushes.
In particular, in the case of DVD players, which have become remarkably widespread in recent years, the object lens of the optical pick-up is extremely small, and therefore it is highly susceptible to soiling and effective measures against soiling are required. Furthermore, in the case of a device used in a vehicle, such as a car-mounted sound system or navigation system, there is a requirement for the device to be accommodated within a limited space, regardless of the fact that it is liable to the effects of dust, or the like, and hence the device itself must be consolidated in a compact shape. Therefore, in a rotary type lens cleaner such as those described above, the bristle brushes make contact with members which are disposed in the narrow space in the periphery of the optical pick-up and dirt on these is liable to become adhered to the optical pick-up.
In order to counter this, as indicated by Japanese Patent Laid-open Application No. S63-313378 described above, a cleaning cartridge has been proposed whereby, rather than using a rotary type device, cleaning is performed manually by means of an operating lever which is exposed to the outside of the device, but the optical disc devices to which a cartridge type system can be applied are limited. Furthermore, there is also a possibility that the cartridge may impact with the optical pick-up or other members, and it is not appropriate for compact devices. In particular, there is a possibility that the insertion hole or members in the proximity thereof may be damaged by contact with the rod-shaped operating lever. Moreover, since it is necessary to adopt a constitution wherein the actual box-shaped cartridge itself corresponds to the interior of the optical disc device, then the constitution of the cartridge becomes complex, liable to fracturing, and incurs manufacturing costs.